1. Field of the Invention
The present invention relates to a bar-code reader for reading bar codes using reflection of light and a controlling method therefor, and more particularly to a bar-code reader, and a controlling method therefor, used in a POS system in which bar codes are read at supermarket checkout counters, etc. from bar-code labels attached to products and other items, and billing and other processing operations are performed based on the thus read bar-code data.
2. Description of the Related Art
In such a POS system, a POS station terminal is installed at the checkout counter. A bar-code reader (bar-code scanner) for reading bar codes from bar-code labels attached to products and other items is connected by a cable to the POS station terminal, and the CPU contained in the POS station terminal processes the data read by the bar-code reader and controls the keyboard, display, printer, etc.
The bar-code reader comprises a light source which emits a laser beam or the like, an optical device which receives light reflected from a bar-code label and converts it into an electrical signal, and a converter which performs conversion to bar-code data based on the electrical signal.
When billing a purchased item, for example, at a supermarket checkout counter using such a POS system, first the operator brings the bar-code label attached to the purchased item into the reading area of the optical device. Thereupon, the optical device receives light reflected from the bar-code label, then this optical received signal is read and converted into a digital form within the bar-code reader, and the resulting bar-code data is decoded.
When the thus read bar code is identified as the first bar code which is completely read, the bar-code reader transmits the bar-code data to the POS station terminal for billing. At this time, a speaker contained in the bar-code reader produces a short beep tone signifying that the bar-code data has been transmitted to the POS station terminal.
The bar-code reader is equipped with a double reading prevention timer to prevent the same bar-code data being read during a predetermined period of time. If, during the time period of this double reading prevention timer, it is judged that the newly read bar-code data is identical to the just previously read bar-code data, the newly read bar-code data is discarded. However, since the operator does not know that the bar-code data of the newly read bar code has been discarded, the operator continues to perform the reading operation for the bar code in the bar-code reading area, trying to have the bar-code reader read the bar code.
When reading the current bar code by the bar-code reader after reading the previous bar code, if the bar codes are different from each other, no problems occur in the operator""s bar-code reading operation, but when trying to read the same bar code as the just previously read one at this time, the above-described feature poses a problem in the operator""s operation.
The longer the predetermined time period of the timer, the greater the probability of the same product being decoded twice, and the more effective the double reading prevention feature of the bar-code reader; however, if the time period is too long, the operator may erroneously take it that the reading sensitivity is poor, and may try to perform the operation over and over again, since there is no knowing whether the bar code has been decoded successfully. This imposes a considerable stress on the operator. To avoid this, the user sets the time period of the double reading prevention feature to such a length that does not cause a problem in operation. However, setting the time period short will make it difficult for the operator to know whether the double reading prevention feature is working or not, and in this case also, the operator will end up trying to perform the reading operation over and over again.
It is, accordingly, an object of the present invention to reduce a burden on an operator in a bar-code reading operation by making the operator realize that he has to wait, when the same product as the immediately previous product is scanned when the double reading timer is activated.
To solve the above problem, the present invention provides a bar-code reader in a POS system in which a signal obtained by receiving light reflected from a bar-code label is converted into bar-code data and the bar-code data is decoded and transmitted to a station host, wherein the bar-code data is compared with the just previously read bar-code data to determine whether they are identical or not; if the bar-code data is identical to the previous bar-code data, and if a double reading prevention timer is not ON, the bar-code data is transmitted to the station host and, at the same time, a speaker is caused to produce a sound to notify the transmission, but if the double reading prevention timer is ON, the bar-code data is discarded, and a notification signifying the discarding of the data is produced with a higher sound than that used for the transmission notification.